Can sitting silicone go bad?

[Kylash]

Ive got 2 tubs of Smooth-On Smooth-Sil 920 that I got for a project thats going to take longer than I thought, and Im afraid that if I dont use it in time it will go bad, does anyone know more about this, if unmixed silicone can go bad just sitting? Ive had this sitting for about 2 and a half months.

 

[LeMarchand]

I have had a 5 gallon bucket of moldmax 30 and the only thing that happened to the silicone after 18 months was that it became thicker. It still gave good molds as long as you got rid of the airsbubbles. Next time this happens, i'll jsut buy their thinner for RTV and make it thin again.

 

[Trap Joe]

Ive got 2 tubs of Smooth-On Smooth-Sil 920 that I got for a project thats going to take longer than I thought, and Im afraid that if I dont use it in time it will go bad, does anyone know more about this, if unmixed silicone can go bad just sitting? Ive had this sitting for about 2 and a half months.

me the same. It is not as bad as smooth on declair. It will be in good , but thicker condition after 2 years longer than they say it would work. That ´s all..:cool

 

[LeMarchand]

oh, forgot to mention that molds made from silicone that has been sitting for 1-2 years tend to be more rigid, less flexible.

 

[zorg]

ive also used silicone that had been sitting for about 2 years, it worked fine and im getting casts from it no problem.

z

 

[Kylash]

awesome, thanks guys!

 

[DAVIDYR1]

Smooth Sil is one of their Platinum silicone lines and Platinum silicones typically have a far greater shelf life even after they've been opened compared to Tin silicones like MoldMax.
A mold made from MoldMax may weaken after a year or more, also depending on the use it's had where as a platinum based silicone mold can take a lot more strain, and will last significantly longer if mixed and made properly. I'd say you're fine with SS920 for quite some time and shouldnt have any problems with it. A Tin silicone on the other hand can be questionable if left unused for whatever amount of time. Thickening silicone is typical if left unused and with Tin silicones it's the catalyst you need to worry about going bad. Also pigmenting older Tin silicones can significantly weaken them and reduce their overall tear strength.

Again, if it's SS920 then you should be just fine.

David

 

[bluerealm]

I've had silicon sit longer than its shelf life and since it was un opend i was able to just take it back and get a refund or get a replacement kit. I have a local distributor, so i'm not sure if that would be the same if your ordering it over the net.

 

[drusselmeyer]

2 1/2 months is well with the shelf life of most silicones (as long as they have been kept away from temperature extremes.

At about 6 months, you might start noticing problems. Make a small test if you are unsure. The information I have gotten in the past is that the catalyst will go bad long before the silicone.